Fluid collection systems are used, for example, in the fields of medicine and laboratory- or analytical technologies. One example finds application in systems which serve to collect a sample of a body fluid together with an optional analysis of the collected sample in an analytical equipment appropriate for the purpose. In particular, such systems are used to collect blood from a patient and to analyze at least a portion of the collected blood in blood analysis equipment. In this connection it can also be arranged that the collection of blood takes place automatically on a continuous basis. Furthermore, the collection technique can be applied to arterial—as well as venous blood. A subsequent analysis of the blood is then carried out to obtain treatment-relative information about the condition of the patient and thereby facilitate specific treatment and therapy. With the assistance of suitable analytical equipment different blood parameters can be examined—for example, the partial pressure of oxygen and carbon dioxide as well as the degree of oxygen saturation. Other parameters are the pH-value, the haematocrit value or the contents of sodium, calcium or potassium.
Such systems are combined to collect a sample of the body fluid, for example, a blood sample and they are often provided with system components for carrying out an infusion, where the infusion is capable of either being coupled with the analysis of the sample of collected body fluid—or not. In such a system, it is possible to integrate components such as a three-way valve into fluid distribution tubing between the patient and items of equipment being used to his advantage and comprising, in particular, the analytical equipment and an infusion device. With these components it is possible to influence as becomes necessary the stream of body fluids flowing in the distribution tubing connecting the patient with the relevant items of equipment.
In connection with a system for collection and infusion, the need often arises to vary the rate of flow of the infusion solution being fed to the patient through distribution tubing. By reversing the direction of flow, blood can be collected from the patient. A distribution device in the distribution tubing system serves to prepare a sample of blood which can be subsequently examined with the help of analytical equipment. Once the sample has been taken, a further reversal of direction of flow allows the infusion to be continued. Incidentally, this also permits blood residues to be cleaned out of the fluid distribution tubing.
In the case of devices used for collecting a sample of a body fluid, the use of a septum is known. In such a situation, the sample is collected from the distribution tubing by means of a capillary or needle, which is used to penetrate the septum so that the tip of the capillary or needle inside the tubing comes into contact with the body fluid. After the sample has been collected by means of the capillary or needle, the latter is withdrawn again out of the septum. To ensure sterility, the capillary or needle must be sterilized each time before a sample is taken or a new one-time unit must be used each time. In such situations, problems arise because it is necessary to protect both outer sides of the septum against contamination between two sample-taking methods.
It is further known that a body fluid sample can be taken out of fluid distribution tubing by means of an over-pressure valve. The sample collected in this way can be conducted to the desired analytical instrument. Optionally, a three-way valve can also be inserted. When the over-pressure valve is opened, this system presents a direct fluid connection between the distribution tubing of the analytical equipment and the patient. This constitutes an inherent safety risk. Furthermore, problems have been encountered in practice with the valve seal, which means that it is difficult to satisfy the high requirements placed upon the over-pressure valve to function as a sterile barrier between the patient and the analytical equipment. A three-way valve for fluids having 3 positions is known from the document U.S. Pat. No. 4,608,996. In each of the three positions a fluid connection is provided between precisely two of the three external connection ports, namely a sampling port, a patient port, and an outlet port.
A method and a device for monitoring blood chemistry are known from U.S. Pat. No. 5,758,643. The system makes it possible to monitor blood gases and electrolytes. It can collect blood from the circulation of the patient by means of a catheter and pump. The construction of the analytical equipment includes several sensors to determine the different parameters. This unit is located very close to the patient catheter. Following completion of the analysis, the remaining collected blood is returned and the system is rinsed with infusion liquid. An internal monitoring method permits the patient to be connected to the analyzing equipment with connecting tubing of varying lengths and different flow volume capacities.
Furthermore, there is known from U.S. Pat. No. 5,165,406 a sensing arrangement for a combined infusion- and blood analysis system. One sensing arrangement exhibits an electrode arrangement which is mounted in an electrode space.
From the document WO 2007/137285 A2, there is known a valve device in which a structural element containing a hollow space is mounted pivotably such that the hollow space can be brought into fluid connection with two openings formed in the housing in two rotation positions, respectively. Three of the openings located in the housing are provided with connection ports to which the fluid distribution tubing can be coupled.
Document WO 91/18632 describes a valve apparatus in which optionally two separated fluid connection pairs can be connected by means of a hollow space within an inner structural element. The hollow space is formed such that an inlet connection port can be connected alternatively with two outlets.
The document U.S. Pat. No. 3,834,372 discloses a valve apparatus where four connection ports are formed with the opposite connections lying in pairs. In different valve positions, adjacent or opposing connection ports can be connected through a hollow space.
A valve apparatus is also described in the document U.S. Pat. No. 5,466,228 in which an inner structural element is mounted pivotably in a housing which itself has several connection ports in order to connect pairs of connection ports. The hollow space is of such a design that in certain positions adjacent connection ports in the housing are connected together.